A New York Times piece from earlier in the month: "Is physical frailty inevitable as we grow older? That question preoccupies scientists and the middle-aged, particularly when they become the same people. Until recently, the evidence was disheartening. A large number of studies in the past few years showed that after age 40, people typically lose 8 percent or more of their muscle mass each decade, a process that accelerates significantly after age 70. Less muscle mass generally means less strength, mobility and among the elderly, independence. It also has been linked with premature mortality. But a growing body of newer science suggests that such decline may not be inexorable. Exercise, the thinking goes, and you might be able to rewrite the future for your muscles. ... [researchers] recruited 40 competitive runners, cyclists and swimmers. They ranged in age from 40 to 81. ... There was little evidence of deterioration in the older athletes' musculature, however. The athletes in their 70s and 80s had almost as much thigh muscle mass as the athletes in their 40s, with minor if any fat infiltration. The athletes also remained strong. There was, as scientists noted, a drop-off in leg muscle strength around age 60 in both men and women. They weren't as strong as the 50-year-olds, but the differential was not huge, and little additional decline followed. The 70- and 80-year-old athletes were about as strong as those in their 60s. ... We think these are very encouraging results. They suggest strongly that people don't have to lose muscle mass and function as they grow older. The changes that we've assumed were due to aging and therefore were unstoppable seem actually to be caused by inactivity. And that can be changed."